Pathogenesis

Seborrhoeic dermatitis is a papulosquamous disorder affecting the areas with most sebum, such as the scalp, face, and trunk. An association with a yeast infection has been known for over 30 years:

Immunological abnormalities and activation of complement are involved.

There is also an ability to activate the alternative complement pathway.

Malassezia furfur appears to be the species associated with infantile seborrhoeic dermatitis.

Epidemiology

Seborrhoeic dermatitis is extremely common in infants. Many children with the condition are not brought to the attention of the medical services and so the precise incidence is unknown.

Presentation

Seborrhoeic dermatitis presenting in infancy is a very common condition which may be brought to the attention of the health visitor or GP.

In the majority of cases it is a benign self-limiting condition which usually clears spontaneously during the first 12-24 months of life but, in a small number, it can be particularly troublesome and require treatment.

Seborrhoeic dermatitis occurs most commonly in the lipid-rich areas of skin and, in infants, occurs predominantly on the scalp and upper face, producing an appearance which may give rise to some concern from parents.

Cradle cap is very common and usually appears in the first few weeks of life. There are greasy, yellow scaling patches that may eventually coalesce to a thick, scaly layer. The condition is not itchy and the child is not distressed by it.

Other findings may include:

Plaques around the ears, nose and eyebrows.

Sharply demarcated brightly erythematous rash in the groin and perianal area (may be confused with ammoniacal dermatitis or candidiasis).

Investigations

Usually no investigation is required and the diagnosis is made on clinical appearance alone.

Seborrhoeic dermatitis is uncommon in preadolescent children, and tinea capitis is uncommon after adolescence. Dandruff in a child is more likely to represent a fungal infection. A fungal culture may aid the diagnosis but the disease may occur with a negative culture and a positive culture is not diagnostic.

Management

General measures

Seborrhoeic dermatitis in infancy is a benign, self-limiting condition and often the most appropriate management is reassurance for the parents that the condition is not serious and will disappear on its own in good time.

The parents may be advised that massaging the scalp with mineral oil on a regular basis, followed by gently brushing the child's hair, may help to loosen the plaques.They may also benefit from advice on how to apply topical emollients.

Soaking the crusts overnight with white petroleum jelly or a slightly warmed vegetable or olive oil, and shampooing in the morning may be effective.

Pharmacological

Although little research has focused specifically on the treatment of seborrhoeic dermatitis in infants, the condition in adults is very similar and the treatment used in infants is based on this research:

In adults, both topical steroids and topical antifungal agents such as ketoconazole are used with good effect, either as shampoo, cream or lotion.

Although the incidence of side-effects with both agents is very low, antifungal agents appear to be slightly better tolerated and appear to be better at preventing recurrences.

Coal-tar shampoo is also effective.

Steroid creams are not usually advised.

The safety of using antifungal agents in infants has been assessed, using ketoconazole twice a week for 4 weeks and, using this regime, no detectable level of ketoconazole was found in the serum after 4 weeks and there was no change in the liver function test results. If symptoms persist longer than 4 weeks with treatment, specialist advice should be sought.

Do not over-treat because of anxious parents. Treat the child, not the parents.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions.